The present invention relates to ice making equipment of the general type described in U.S. Pat. Nos. 3,228,202; 4,510,768 and application Ser. No. 677,284, now U.S. Pat. No. 4,604,875, all of which are incorporated herein by reference. While this equipment is very good, there are certain areas in which improvements are possible. In this equipment, an ice sheet produced in an ice forming chamber is transferred at timed intervals to a storage chamber and is simultaneously broken into ice pieces. However, changes in operating conditions may cause the thickness of the ice sheet to vary. Consequently, because of differences in ambient conditions, the thickness of the pieces formed may differ from one time of the day to another or from one machine installation to another. In addition, several other events in the operating cycle were actuated by a timer, i.e., by allowing a predetermined interval of time to elapse before operating various valves and other machine elements. With this method of operation it is possible for certain machine functions to be performed before others have been completed resulting, for example, from a jam-up caused by parts freezing together, etc. Consequently, control of the operation has not always been as positive as desired.
In some of the equipment previously described, ice is transferred from the freezing chamber by a plunger operated with tap water and because excess water must be disposed of, e.g., by allowing it to flow into a storage basin, no more water should be frozen than that volume used to move the plunger during one stroke. If more water than this is required, an overflow basin is needed to store the excess water which upon becoming full will either shut down the machine or spill which is, of course, undesirable. Accordingly, it is an objective to provide a balanced control system wherein the thickness of the ice is always correctly related to the amount of water required to move the plunger as well as a provision for preventing ice sheet thickness fluctuations that might result from variations in ambient conditions. A further object of the invention is to provide an ice sheet transferring mechanism that is not dependent upon tap water for its operation and which will reliably move the ice stripping plunger between two fixed points preferably with the ice stripping action commencing at whatever time interval is required for the ice sheet to build to a predetermined thickness.
These and other more detailed and specific objects of the invention will become apparent in view of the following description setting forth in detail certain illustrative embodiments of the invention by way of example.